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<h1 class="title">mdichild.cpp 示例文件</h1>
<span class="subtitle">mainwindows/mdi/mdichild.cpp</span>
<!-- $$$mainwindows/mdi/mdichild.cpp-description -->
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<pre class="cpp">

  <span class="comment">/****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
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  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, you may use this file under the terms of the BSD license
  ** as follows:
  **
  ** &quot;Redistribution and use in source and binary forms, with or without
  ** modification, are permitted provided that the following conditions are
  ** met:
  **   * Redistributions of source code must retain the above copyright
  **     notice, this list of conditions and the following disclaimer.
  **   * Redistributions in binary form must reproduce the above copyright
  **     notice, this list of conditions and the following disclaimer in
  **     the documentation and/or other materials provided with the
  **     distribution.
  **   * Neither the name of The Qt Company Ltd nor the names of its
  **     contributors may be used to endorse or promote products derived
  **     from this software without specific prior written permission.
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  ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  ** &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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  ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.&quot;
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/</span>

  <span class="preprocessor">#include &lt;QtWidgets&gt;</span>

  <span class="preprocessor">#include &quot;mdichild.h&quot;</span>

  MdiChild<span class="operator">::</span>MdiChild()
  {
      setAttribute(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WA_DeleteOnClose);
      isUntitled <span class="operator">=</span> <span class="keyword">true</span>;
  }

  <span class="type">void</span> MdiChild<span class="operator">::</span>newFile()
  {
      <span class="keyword">static</span> <span class="type">int</span> sequenceNumber <span class="operator">=</span> <span class="number">1</span>;

      isUntitled <span class="operator">=</span> <span class="keyword">true</span>;
      curFile <span class="operator">=</span> tr(<span class="string">&quot;document%1.txt&quot;</span>)<span class="operator">.</span>arg(sequenceNumber<span class="operator">+</span><span class="operator">+</span>);
      setWindowTitle(curFile <span class="operator">+</span> <span class="string">&quot;[*]&quot;</span>);

      connect(document()<span class="operator">,</span> <span class="operator">&amp;</span><span class="type"><a href="../qtgui/qtextdocument.html">QTextDocument</a></span><span class="operator">::</span>contentsChanged<span class="operator">,</span>
              <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&amp;</span>MdiChild<span class="operator">::</span>documentWasModified);
  }

  bool MdiChild<span class="operator">::</span>loadFile(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&amp;</span>fileName)
  {
      <span class="type"><a href="../qtcore/qfile.html">QFile</a></span> file(fileName);
      <span class="keyword">if</span> (<span class="operator">!</span>file<span class="operator">.</span>open(<span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>ReadOnly <span class="operator">|</span> <span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>Text)) {
          <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">&quot;MDI&quot;</span>)<span class="operator">,</span>
                               tr(<span class="string">&quot;Cannot read file %1:\n%2.&quot;</span>)
                               <span class="operator">.</span>arg(fileName)
                               <span class="operator">.</span>arg(file<span class="operator">.</span>errorString()));
          <span class="keyword">return</span> <span class="keyword">false</span>;
      }

      <span class="type"><a href="../qtcore/qtextstream.html">QTextStream</a></span> in(<span class="operator">&amp;</span>file);
      <span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>setOverrideCursor(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WaitCursor);
      setPlainText(in<span class="operator">.</span>readAll());
      <span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>restoreOverrideCursor();

      setCurrentFile(fileName);

      connect(document()<span class="operator">,</span> <span class="operator">&amp;</span><span class="type"><a href="../qtgui/qtextdocument.html">QTextDocument</a></span><span class="operator">::</span>contentsChanged<span class="operator">,</span>
              <span class="keyword">this</span><span class="operator">,</span> <span class="operator">&amp;</span>MdiChild<span class="operator">::</span>documentWasModified);

      <span class="keyword">return</span> <span class="keyword">true</span>;
  }

  bool MdiChild<span class="operator">::</span>save()
  {
      <span class="keyword">if</span> (isUntitled) {
          <span class="keyword">return</span> saveAs();
      } <span class="keyword">else</span> {
          <span class="keyword">return</span> saveFile(curFile);
      }
  }

  bool MdiChild<span class="operator">::</span>saveAs()
  {
      <span class="type"><a href="../qtcore/qstring.html">QString</a></span> fileName <span class="operator">=</span> <span class="type"><a href="qfiledialog.html">QFileDialog</a></span><span class="operator">::</span>getSaveFileName(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">&quot;Save As&quot;</span>)<span class="operator">,</span>
                                                      curFile);
      <span class="keyword">if</span> (fileName<span class="operator">.</span>isEmpty())
          <span class="keyword">return</span> <span class="keyword">false</span>;

      <span class="keyword">return</span> saveFile(fileName);
  }

  bool MdiChild<span class="operator">::</span>saveFile(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&amp;</span>fileName)
  {
      <span class="type"><a href="../qtcore/qfile.html">QFile</a></span> file(fileName);
      <span class="keyword">if</span> (<span class="operator">!</span>file<span class="operator">.</span>open(<span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>WriteOnly <span class="operator">|</span> <span class="type"><a href="../qtcore/qfile.html">QFile</a></span><span class="operator">::</span>Text)) {
          <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">&quot;MDI&quot;</span>)<span class="operator">,</span>
                               tr(<span class="string">&quot;Cannot write file %1:\n%2.&quot;</span>)
                               <span class="operator">.</span>arg(<span class="type"><a href="../qtcore/qdir.html">QDir</a></span><span class="operator">::</span>toNativeSeparators(fileName)<span class="operator">,</span> file<span class="operator">.</span>errorString()));
          <span class="keyword">return</span> <span class="keyword">false</span>;
      }

      <span class="type"><a href="../qtcore/qtextstream.html">QTextStream</a></span> out(<span class="operator">&amp;</span>file);
      <span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>setOverrideCursor(<span class="type"><a href="../qtcore/qt.html">Qt</a></span><span class="operator">::</span>WaitCursor);
      out <span class="operator">&lt;</span><span class="operator">&lt;</span> toPlainText();
      <span class="type"><a href="qapplication.html">QApplication</a></span><span class="operator">::</span>restoreOverrideCursor();

      setCurrentFile(fileName);
      <span class="keyword">return</span> <span class="keyword">true</span>;
  }

  <span class="type"><a href="../qtcore/qstring.html">QString</a></span> MdiChild<span class="operator">::</span>userFriendlyCurrentFile()
  {
      <span class="keyword">return</span> strippedName(curFile);
  }

  <span class="type">void</span> MdiChild<span class="operator">::</span>closeEvent(<span class="type"><a href="../qtgui/qcloseevent.html">QCloseEvent</a></span> <span class="operator">*</span>event)
  {
      <span class="keyword">if</span> (maybeSave()) {
          event<span class="operator">-</span><span class="operator">&gt;</span>accept();
      } <span class="keyword">else</span> {
          event<span class="operator">-</span><span class="operator">&gt;</span>ignore();
      }
  }

  <span class="type">void</span> MdiChild<span class="operator">::</span>documentWasModified()
  {
      setWindowModified(document()<span class="operator">-</span><span class="operator">&gt;</span>isModified());
  }

  bool MdiChild<span class="operator">::</span>maybeSave()
  {
      <span class="keyword">if</span> (<span class="operator">!</span>document()<span class="operator">-</span><span class="operator">&gt;</span>isModified())
          <span class="keyword">return</span> <span class="keyword">true</span>;
      <span class="keyword">const</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>StandardButton ret
              <span class="operator">=</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>warning(<span class="keyword">this</span><span class="operator">,</span> tr(<span class="string">&quot;MDI&quot;</span>)<span class="operator">,</span>
                                     tr(<span class="string">&quot;'%1' has been modified.\n&quot;</span>
                                        <span class="string">&quot;Do you want to save your changes?&quot;</span>)
                                     <span class="operator">.</span>arg(userFriendlyCurrentFile())<span class="operator">,</span>
                                     <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Save <span class="operator">|</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Discard
                                     <span class="operator">|</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Cancel);
      <span class="keyword">switch</span> (ret) {
      <span class="keyword">case</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Save:
          <span class="keyword">return</span> save();
      <span class="keyword">case</span> <span class="type"><a href="qmessagebox.html">QMessageBox</a></span><span class="operator">::</span>Cancel:
          <span class="keyword">return</span> <span class="keyword">false</span>;
      <span class="keyword">default</span>:
          <span class="keyword">break</span>;
      }
      <span class="keyword">return</span> <span class="keyword">true</span>;
  }

  <span class="type">void</span> MdiChild<span class="operator">::</span>setCurrentFile(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&amp;</span>fileName)
  {
      curFile <span class="operator">=</span> <span class="type"><a href="../qtcore/qfileinfo.html">QFileInfo</a></span>(fileName)<span class="operator">.</span>canonicalFilePath();
      isUntitled <span class="operator">=</span> <span class="keyword">false</span>;
      document()<span class="operator">-</span><span class="operator">&gt;</span>setModified(<span class="keyword">false</span>);
      setWindowModified(<span class="keyword">false</span>);
      setWindowTitle(userFriendlyCurrentFile() <span class="operator">+</span> <span class="string">&quot;[*]&quot;</span>);
  }

  <span class="type"><a href="../qtcore/qstring.html">QString</a></span> MdiChild<span class="operator">::</span>strippedName(<span class="keyword">const</span> <span class="type"><a href="../qtcore/qstring.html">QString</a></span> <span class="operator">&amp;</span>fullFileName)
  {
      <span class="keyword">return</span> <span class="type"><a href="../qtcore/qfileinfo.html">QFileInfo</a></span>(fullFileName)<span class="operator">.</span>fileName();
  }

</pre>
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<!-- @@@mainwindows/mdi/mdichild.cpp -->
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